From the website of the Legislative Yuan:
The first step in the legislative process is the proposal of bills. Regular bills may come from: the Executive Yuan, the Judicial Yuan, the Examination Yuan, the Control Yuan, members of the Legislative Yuan and party caucuses under the Organic Law of the Legislative Yuan. Budgetary bills, however, shall be prepared only by the Executive Yuan.
Legislative Yuan -Legislative Procedure
This is from a translation of Article 58 of the ROC Constitution, in pertinent part:
Statutory or budgetary bills or bills concerning martial law, amnesty, declaration of war, conclusion of peace or treaties, and other important affairs, all of which are to be submitted to the Legislative Yuan, as well as matters that are of common concern to the various Ministries and Commissions, shall be presented by the President and various Ministers and Chairmen of Commissions of the Executive Yuan to the Executive Yuan Council for decision.
This appears to link to the original Chinese version of Article 58: